Development of Small-pitch, Ultra-thin 3D Silicon Sensors at USTC

TL;DR

This paper details the development and characterization of ultra-thin, small-pitch 3D silicon sensors at USTC, aiming for precise position and time measurements at the single-pixel level.

Contribution

It introduces a new 3D silicon sensor design with ultra-thin active layers and small pixels, advancing sensor technology for high-precision measurements.

Findings

Successful fabrication of sensors with 50 um and 25 um pixel sizes.

First sensor run completed with a merged wafer layout.

Sensors demonstrate promising performance for position and time measurement.

Abstract

We report on the development of 3D silicon sensors at the University of Science and Technology of China (USTC). The sensor involves columnar electrodes (5 um in diameter) of both doping types, etched from the same wafer side. The p+ electrodes pass through the epitaxial wafer, whereas the n+ electrodes stop at a short distance from the opposite side of the epitaxial wafer. With respect to previous generations of 3D sensors, they feature an ultra-thin active substrate (50 um) and a small pixel size of 50 um x 50 um or 25 um x 25 um. This R&D project aims to establish a sensor technology to simultaneously measure position and time information at the single-pixel level. The first run with one merged wafer layout has been completed. The design, fabrication, and characterization of the sensors are reported in this paper.